A head-mounted display (hereinafter also referred to as an “HMD”) is worn on a user's head to provide a world of virtual reality (VR) to the user. Recent years have seen the emergence of applications that allow the user to play a game while at the same time watching s screen displayed on the HMD. In an existing stationary display such as television receiver, a user's field-of-view range spreads beyond the screen, possibly rendering it impossible for the user to focus on the screen or resulting in less-than-enough sense of immersion. In that regard, when wearing an HMD, the user only sees a video displayed on the HMD, increasing the sense of immersion into the world of video and further enhancing entertaining nature of the game.